The Question:
When a character attempts a specific result Test of Wills, when does the result action happen?

This capaign started in media res with a big mass combat. Several rounds in, Player A attempted to intimidate the enemy NPCs, by saying "Drop your weapons". He succeeded (with sveral Aces on his die) with 3-4 raises. I said he was successful, but I think the NPCs reaction happens on their turn, so they did not immediately drop their weapons (which they were going to do).

The next action was Player B, who attacked, beacuse the NPCs didnt react to the intimidation. He dropped another NPC.

Then the NPCs turn came up and they immediately dropped their weapons and surreneded.

Is this the correct way the Test of WIlls should happen in combat, or for a more role playing (non-combat) result during comabt should they NPCs have immeditaly dropped their weapons on Player As turn?

The Question:
When a character attempts a specific result Test of Wills, when does the result action happen?

This capaign started in media res with a big mass combat. Several rounds in, Player A attempted to intimidate the enemy NPCs, by saying "Drop your weapons". He succeeded (with sveral Aces on his die) with 3-4 raises. I said he was successful, but I think the NPCs reaction happens on their turn, so they did not immediately drop their weapons (which they were going to do).

The next action was Player B, who attacked, beacuse the NPCs didnt react to the intimidation. He dropped another NPC.

Then the NPCs turn came up and they immediately dropped their weapons and surreneded.

Is this the correct way the Test of WIlls should happen in combat, or for a more role playing (non-combat) result during comabt should they NPCs have immeditaly dropped their weapons on Player As turn?

The "mechanical" effect of a Test of Wills is that the subject could be Shaken and the character might get a +2 to their next action against them. Those would take effect "immediately."

But once the NPCs were reacting to what the Player specifically said; that was effectively roleplaying and not defined by those "mechanics" per se.

Really, once they surrendered, you could say combat was over, and initiative wasn't really a concern anymore.

Personally, I still like the way you ran it, but if Player B wanted to see if they were going to surrender, he should have gone on Hold to see what their action would be. If they went to attack, he could attempt to interrupt. It's a perfect use of the interrupt rules.

I like that way because you can end up with the classic movie moment where someone gets shot/killed/whatever just because they haven't had a chance to react yet. Could be a vengeful character or someone who doesn't want the enemy to talk and reveal secret plans or maybe a sniper who misunderstands unholstering a weapon to relinquish it with unholstering to use it.

Either way could work. Really, both could be used simply depending on the situation.